Range finder system and electronic system having same

ABSTRACT

A range finder system ( 100 ) includes a point light source ( 10 ), image pickup devices ( 20 ), ( 30 ), and a processing device ( 50 ). The point light source ( 10 ) emits light. The image pickup devices ( 20 ), ( 30 ) include lenses ( 22 ), ( 32 ) and sensors ( 24 ), ( 34 ), respectively. The lenses have focal lengths F 1 , F 2  and the sensors ( 24 ), ( 34 ) have light-received units. The processing device ( 50 ) is electrically coupled to the image pickup devices ( 20 ), ( 30 ). The processing device ( 50 ) calculates distance D 1 , D 2  from locations of images of the point light source ( 10 ) on the light-received units to centers of the sensors ( 24 ), ( 34 ), respectively. A distance X from the point light source ( 10 ) to the first lens ( 22 ) and the second lens ( 32 ) is determined based on the ratio of D 1  to F 1  and the ratio of D 2  to F 2 .

BACKGROUND

1. Technical Field

The invention relates to electronic systems and range finder systems,and particularly to an electronic system and a range finder system usinglight to measure the distance between two target objects.

2. Description of Related Art

Range finding refers to a technique for determining the range, ordistance, to a target. Currently, range finders are widely used in manyfields, such as in engineering. The range finders are developed toimprove the labor-consuming property existing in a conventional methodfor measuring a distance with a ruler or a conventional distancemeasurement device with a calibration rod.

A laser range finder using a laser beam to determine a distance to atarget object is employed extensively in distance measurements. Thelaser range finder is operated based on the principle of sending a laserpulse toward the target object, and then receiving a laser signalreflected off the target object, whereby a traveling time of the lasersignal is measured and the distance to the target object is obtainedaccordingly.

The electronic devices, such as a TV or a game console, and a remotecontrol should have a particular distance therebetween so as to allowthem operate effectively. That is, the user holding the remote controlis limited to be in an effective range to control the electronicdevices. Therefore, it is need to incorporate a capacity for measuring adistance into the remote control or the electronic devices to facilitatethe usage thereof. However, the laser range finder mentioned above iscostly and not suitable to be employed in the electronic devices or theremote control due to their complicated structure.

What is needed, therefore, is an electronic system and a range findersystem having simple structures.

SUMMARY

A range finder system is provided. In one embodiment, the range findersystem includes a point light source, a first image pickup device, asecond image pickup device and a processing device. The point lightsource is configured to emit light. The first image pickup deviceincludes a first lens and a first sensor disposed corresponding to thefirst lens. The first lens has a first focal length F₁. The first sensorhas a first light-received unit. The second image pickup device isspaced apart from the first image pickup device a predetermined distanceL. The second image pickup device includes a second lens and a secondsensor disposed corresponding to the second lens. The second lens has asecond focal length F₂. The second sensor has a second light-receivedunit. The processing device is electronically coupled to the first imagepickup device and the second image pickup device. The processing deviceis configured to calculate a first distance D₁ from a location of animage of the point light source on the first light-received unit to acenter of the first sensor, and a second distance D₂ from a location ofthe image of the point light source on the second light-received unit toa center of the second sensor. The processing device calculates aperpendicular distance from the point light source to a line connectingthe first lens and the second lens based on the ratio of D₁ to F₁ andthe ratio of D₂ to F₂.

Another range finder system for calculating a distance X is provided. Inone embodiment, the range finder system includes a point light source, afirst image pickup device, a second image pickup device and a processingdevice. The point light source is configured to emit light. The firstimage pickup device includes a first lens and a first sensor disposedcorresponding to the first lens. The first lens has a first focal lengthF₁. The first sensor has a first light-received unit for receiving theemitted light. The second image pickup device is spaced apart from thefirst image pickup device a predetermined distance L. The second imagepickup device includes a second lens and a second sensor disposedcorresponding to the second lens. The second lens has a second focallength F₂. The second sensor has a second light-received unit forreceiving the emitted light. The processing device is electronicallycoupled to the first image pickup device and the second image pickupdevice. The processing device is configured to calculate a firstdistance D₁ from a location of an image of the point light source on thefirst light-received unit to a center of the first sensor, and a seconddistance D₂ from a location of the image of the point light source onthe second light-received unit to a center of the second sensor. Theprocessing device calculates the distance X defined by the followingequation:

$X = \frac{L \times \tan \; \theta_{1} \times \tan \; \theta_{2}}{{\tan \; \theta_{1}} + {\tan \; \theta_{2}}}$

.where θ₁ is a complementary angle for an angle of θ₃ determined basedon the ratio of D₁ to F₁, and θ₂ is a complementary angle for an angleof θ₄ determined based on the ratio of D₂ to F₂.

An electronic system is provided. In one embodiment, the electronicsystem includes a first electronic device and a second electronicdevice. The first electronic device includes a point light source foremitting light. The second electronic device includes a first imagepickup device, a second image pickup device and a processing device. Thefirst image pickup device includes a first lens and a first sensordisposed corresponding to the first lens. The first lens has a firstfocal length F₁. The first sensor has a first light-received unit. Thesecond image pickup device is spaced apart from the first image pickupdevice a predetermined distance L. The second image pickup deviceincludes a second lens and a second sensor disposed corresponding to thesecond lens. The second lens has a second focal length F₂. The secondsensor has a second light-received unit. The processing device iselectronically coupled to the first image pickup device and the secondimage pickup device. The processing device is configured for calculatinga first distance D₁ from a location of an image of the point lightsource on the first light-received unit to a center of the first sensor,and a second distance D₂ from a location of the image of the point lightsource on the second light-received units to a center of the secondsensor. The processing device calculates a perpendicular distancebetween the first electronic device and the second electronic devicebased on the ratio of D₁ to F₁ and the ratio of D₂ to F₂.

Advantages and novel features of the present range finder system,electronic system and method for measuring distance will become moreapparent from the following detailed description of preferredembodiments when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawing are not necessarily drawn to scale, theemphasis instead being placed upon clearly illustrating the principlesof the present invention.

FIG. 1 is a schematic view of a range finder system in accordance with apreferred embodiment of the present invention;

FIG. 2 is a schematic view of an electronic system in accordance with apreferred embodiment of the present invention; and

FIG. 3 is a schematic view of another electronic system in accordancewith a preferred embodiment of the present invention.

Corresponding reference characters indicate corresponding partsthroughout the drawings. The exemplifications set out herein illustrateat least one preferred embodiment of the present range finder system,electronic system and method for measuring distance, in one form, andsuch exemplifications are not to be construed as limiting the scope ofthe invention in any manner.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made to the drawings to describe embodiments ofthe present range finder system and the electronic system in detail.

Referring to FIG. 1, a range finder system 100 in accordance with apresent embodiment, is shown. The range finder system 100 includes apoint light source 10, a first image pickup device 20, a second imagepickup device 30, and a processing device 50.

The point light source 10 is configured to emit light toward the firstimage pickup device 20 and the second image pickup device 30. Forexample, the light beams C₁ and C₂ are received by the first imagepickup device 20 and the second image pickup device 30, respectively. Inthe present embodiment, the point light source 10 can be a lightemitting device for emitting visible light or invisible light, such as ahalogen lamp, a fluorescent lamp or a light emitting diode (LED). Inaddition, the opposite position between the point light source 10 andthe image pickup device 30, 50 is capable to vary and not limited toexemplification illustrated in FIG. 1.

The first image pickup device 20 and the second image pickup device 30are disposed appropriately adjacent to each other so as to be able toreceive the light emitting from the point light source 10. Inparticular, the first image pickup device 20 is spaced apart from thesecond image pickup device 30 a predetermined distance L. The firstimage pickup device 20 includes a first lens 22 and a first sensor 24while the second image pickup device 30 includes a second lens 32 and asecond sensor 34. In the present embodiment, the first lens 22 and thesecond lens 32 are converging lenses. In addition, the first lens 22 hasa first focal length F₁ and the second lens 32 has a second focal lengthF₂. The first sensor 24 and the second sensor 34 has a firstlight-received unit 26 and a second light-received unit 36,respectively, to receive light emitting from the point light source 10.Referring to FIG. 1, the light beams C₁ and C₂ pass through a center ofthe first lens 22 and a center of the second lens 32, and then fall onthe first sensor 24 and the second sensor 36, respectively. In thisembodiment, the first sensor 24 or the second sensor 34 can be acharge-coupled device (CCD) or a complementary metal-oxide semiconductor(CMOS).

The processing device 50 is electronically coupled to the first imagepickup device 20 and the second image pickup device 30. Particularly,the processing device 50 connects to the first sensor 24 and the secondsensor 34. In the present embodiment, the processing device 50, forexample, can include at least one signal processing circuit and at leastone electronic element. Alternatively, the signal processing circuit andthe electronic element can be integrated into a chip to act as theprocessing device 50.

In the present embodiment, when the point light source 10 are far awayfrom the first image pickup device 20 and the second image pickup device30, it is assumed that the light emitted from the point light source 10are parallel. The parallel light pass through the converging lenses willbe converged to a point where an image is formed. Referring to FIG. 1,the first light-received unit 26 of the first sensor 24 is the placewhere the light beam C₁ falls and an image of the point light source 10formed. The second light-received unit 36 of the second sensor 34 is theplace where the light beam C₂ falls and an image of the point lightsource 10 formed. A first distance D₁ from a location of the image onthe first light-received unit 26 to a center of the first sensor 24 iscalculated by the processing device 50 and then the value of D₁ isoutputted. A second distance D₂ from a location of the image on thesecond light-received unit 36 to a center of the second sensor 34 isalso calculated by the processing device 50 and then the value of D₂ isoutputted.

As mentioned above, the values of D₁ and D₂ are referred to obtain adistance between the point light source 10 and the image pickup devices20, 30. If the sensors 24, 34 are very close to the lens 22, 32, aperpendicular distance X from the point light source 10 to a line C₃connecting the first lens 22 and the second lens 32 can be substantiallyequal to the distance between the point light source 10 and the imagepickup devices 20, 30. In the present embodiment, the first sensor 24and the second sensor 34 are placed around the focal lengths F₁ and F₂of the first lens 22 and the second lens 32, respectively.

In the present embodiment, the perpendicular distance X is determinedbased on the trigonometric functions. Specifically, the values of D₁ andF₁ represent the lengths of two sides of a right triangle containing anangle θ₃ while the values of D₂ and F₂ represent the lengths of twosides of a right triangle containing an angle θ₄. That is, the value ofD₁ is the length of side opposite to the angle θ₃. The value of D₂ isthe length of side opposite to the angles θ₄. The value of F₁ is thelength of side in contact with the angle θ₃ and the right angle. Thevalue of F₂ is the length of side in contact with the angle θ₄ and theright angle. Accordingly, the value of the angle θ₃ can be obtained by afunction of the tangent of the angle θ₃, i.e. the ratio of D₁ to F₁, andthe value of the angle θ₄ can be obtained by a function of the tangentof the angle θ₄, i.e. the ratio of D₂ to F₂. In addition, a firstincluded angle θ₁ between the light beam C₁ incident into the first lens22 and the line C₃, which is the complementary angle for the angle ofθ₃, can be obtained accordingly. A second included angle θ₂ between thelight beam C₂ incident into the second lens 32 and the line C₃, which isthe complementary angle for the angle of θ₄, also can be obtained.Finally, the perpendicular distance X can be obtained using thefollowing equation:

$X = \frac{L \times \tan \; \theta_{1} \times \tan \; \theta_{2}}{{\tan \; \theta_{1}} + {\tan \; \theta_{2}}}$

Additionally, a method for measuring a distance X between a first placeA and a second place B, according to a present embodiment, is shown. Inthis case, the first place A places a point light source 10 while thesecond place B places a first image pickup device 20 and a second imagepickup device 30. A processing device 50 is electrically coupled to thefirst image pickup device 20 and the second image pickup device 30. Thesecond image pickup device 30 is spaced apart from the first pickupdevice 20 a predetermined distance L. The first image pickup device 20has a first lens 22 and a first sensor 24 disposed corresponding to thefirst lens 20. The first lens 22 has a first focal length F₁. The firstsensor 24 has a first light-received unit. The second image pickupdevice 30 has a second lens 32 and a second sensor 34 disposedcorresponding to the second lens 32. The second lens 32 has a secondfocal length F₂. The second sensor 34 has a second light-received unit.The method includes the following steps:

(a): emitting light from the point light source 10 toward the firstimage pickup device 20 and the second image pickup device 30;(b): receiving the light by the first sensor 24 of the first imagepickup device 20 and the second sensor 34 of the second image pickupdevice 30;(c): obtaining a first distance D₁ from a location of an image of thepoint light source 10 on the first light-received unit 26 to a center ofthe first sensor 26, and a second distance D₂ from a location of theimage of the point light source 10 on the second light-received unit 36to a center of the second sensor 34; and(d): obtaining a perpendicular distance X between the first place A andthe second place B based on the ratio of D₁ to F₁ and the ratio of D₂ toF₂.

Each step of the present method is described in greater detail below. Inthe present embodiment, because compositions, functions andcharacteristics of the point light source 10, the first image pickupdevice 20 and the second image pickup device 30 are similar to the sameelements mentioned above, the detailed description is omitted for sakeof conciseness.

In step (a), the point light source 10 at the first place A emits thelight toward the first image pickup device 20 and the second imagepickup device 30 at the second place B. Referring to FIG. 1, the lightbeams C₁ and C₂ from the point light source 10 pass through centers ofthe first lens 22 and the second lens 32 to fall on the first sensor 26and the second sensor 36, respectively.

In step (b), the first sensor 24 of the first image pickup device 20 andthe second sensor 34 of the second image pickup device 30 receive thelight beams C₁ and C₂, respectively. In particular, the light beam C₁passes through the center of the first lens 22 and then received by thefirst light received unit 26 of the first sensor 24 while the light C₂passes through the center of the second lens 32 and then received by thesecond light received unit 36 of the second sensor 34.

In step (c), the first distance D₁ and the second distance D₂ arecalculated by the processing device 50. In the present embodiment, thevalues of D₁ and D₂ are configured for facilitating calculation of theperpendicular distance X between the first place A and the second placeB.

In step (d), the perpendicular distance X between the first place A andthe second place B is calculated by the processing device 50. In thepresent embodiment, the step (d) includes the steps described asfollows.

(d1): calculating the ratio of D₁ to F₁ so as to obtain a first includedangle θ₁ between the light beam C₁ incident into the first lens 22 and aline C₃ connecting the first lens 22 and the second lens 32;(d2): calculating the ratio of D₂ to F₂ so as to obtain a secondincluded angle θ₂ between the light beam C₂ incident into the secondlens 32 and a line C₃ connecting the first lens 22 and the second lens32; and(d3): calculating a relationship between the values of θ₁, θ₂, and L toobtain the perpendicular distance X from the point light source 10 tothe line C₃.

As mentioned above, in step (d1), the value of the angle θ₃ can beobtained by deriving from the tangent function of the angle θ₃, i.e. theratio of D₁ to F₁. Moreover, in step (d2), the value of the angle θ₄ canbe obtained by deriving from the tangent function of the angle θ₄, i.e.the ratio of D₂ to F₂. Thus, the complementary angles for the angle θ₃angle θ₄, i.e. the angle θ₁ and θ₂, can be obtained. Accordingly, theperpendicular distance X can be obtained by calculating the relationshipof the values of θ₁, θ₂, and L. In particular, the perpendiculardistance X can be obtained by the following equation:

$X = \frac{L \times \tan \; \theta_{1} \times \tan \; \theta_{2}}{{\tan \; \theta_{1}} + {\tan \; \theta_{2}}}$

Additionally, referring to the FIG. 2 and FIG. 3, an electronic system100 in accordance with a present embodiment, is shown. The electronicsystem 100 includes a first electronic device 200 and a secondelectronic device 400. The first electronic device 200 includes a pointlight source 10. The second electronic device 400 includes a first imagepickup device 20, a second image pickup device 30 and a processingdevice 50.

However, because compositions, functions and characteristics of thepoint light source 10, the first image pickup device 20, the secondimage pickup device 30, and the processing device 50 are similar to thesame elements mentioned above, the detailed description is omitted forsake of conciseness. Moreover, the perpendicular distance between thefirst electronic device 200 and the second electronic device 400 isobtained based on the trigonometric functions and the principledescribed above.

In the present embodiment, as shown in FIG. 2, the first electronicdevice 200 is a display device, such as a LCD, while the secondelectronic device 400 is a remote control. Alternatively, as shown inFIG. 3, the first electronic device 500 is a remote control while thesecond electronic device 300 is a display device.

Finally, it is to be understood that the above-described embodiments areintended to illustrate rather than limit the invention. Variations maybe made to the embodiments without departing from the spirit of theinvention as claimed. The above-described embodiments illustrate thescope of the invention but do not restrict the scope of the invention.

1. A range finder system, comprising: a point light source configured toemit light; a first image pickup device comprising a first lens and afirst sensor disposed corresponding to the first lens, the first lenshaving a first focal length F₁, the first sensor having a firstlight-received unit; a second image pickup device spaced apart from thefirst image pickup device a predetermined distance L, the second imagepickup device comprising a second lens and a second sensor disposedcorresponding to the second lens, the second lens having a second focallength F₂, the second sensor having a second light-received unit; and aprocessing device electronically coupled to the first image pickupdevice and the second image pickup device, the processing device beingconfigured for calculating a first distance D₁ from a location of animage of the point light source on the first light-received unit to acenter of the first sensor and a second distance D₂ from a location ofthe image of the point light source on the second light-received unit toa center of the second sensor, and calculating a perpendicular distancefrom the point light source to a line connecting the first lens and thesecond lens based on the ratio of D₁ to F₁ and the ratio of D₂ to F₂. 2.The range finder system as claimed in claim 1, wherein the point lightsource is a halogen lamp, a fluorescent lamp or a light emitter diode.3. The range finder system as claimed in claim 1, wherein the firstimage pickup device or the second image pickup device is acharge-coupled device or a complementary metal-oxide semiconductor.
 4. Arange finder system for calculating a distant X, comprising: a pointlight source configured to emit light; a first image pickup devicecomprising a first lens and a first sensor disposed corresponding to thefirst lens, the first lens having a first focal length F₁, the firstsensor having a first light-received unit for receiving the emittedlight; a second image pickup device spaced apart from the first imagepickup device a predetermined distance L, the second image pickup devicecomprising a second lens and a second sensor disposed corresponding tothe second lens, the second lens having a second focal length F₂, thesecond sensor having a second light-received unit for receiving theemitted light; and a processing device electronically coupled to thefirst image pickup device and the second image pickup device, theprocessing device configured for calculating a first distance D₁ from alocation of an image of the point light source on the firstlight-received unit to a center of the first sensor and a seconddistance D₂ from a location of the image of the point light source onthe second light-received unit to a center of the second sensor, andcalculating the distance X defined by the following equation:$X = \frac{L \times \tan \; \theta_{1} \times \tan \; \theta_{2}}{{\tan \; \theta_{1}} + {\tan \; \theta_{2}}}$where θ₁ is a complementary angle for an angle of θ₃, the tangent ofwhich is the ratio of D₁ to F₁, and θ₂ is a complementary angle for anangle of θ₄, the tangent of which is the ratio of D₂ to F₂.
 5. Anelectronic system, comprising: a first electronic device comprising apoint light source for emitting light; and a second electronic devicecomprising a first image pickup device, a second image pickup device anda processing device, the first image pickup device comprising a firstlens and a first sensor disposed corresponding to the first lens, thefirst lens having a first focal length F₁, the first sensor having afirst light-received unit, the second image pickup device being spacedapart from the first image pickup device a predetermined distance L, thesecond image pickup device comprising a second lens and a second sensordisposed corresponding to the second lens, the second lens having asecond focal length F₂, the second sensor having a second light-receivedunit, the processing device being electronically coupled to the firstimage pickup device and the second image pickup device, the processingdevice configured for calculating a first distance D₁ from a location ofan image of the point light source on the first light-received unit to acenter of the first sensor and a second distance D₂ from a location ofthe image of the point light source on the second light-received unit toa center of the second sensor, and calculating a perpendicular distanceX between the first electronic device and the second electronic devicebased on the ratio of D₁ to F₁ and the ratio of D₂ to F₂.
 6. Theelectronic system as claimed in claim 5, wherein the point light sourceis a halogen lamp, a fluorescent lamp or a light emitter diode.
 7. Theelectronic system as claimed in claim 5, wherein the first image pickupdevice or the second image pickup device is a charge-coupled device or acomplementary metal-oxide-semiconductor.
 8. The electronic system asclaimed in claim 5, wherein the first electronic device is a displaydevice and the second electronic device is a remote control.
 9. Theelectronic system as claimed in claim 5, wherein the first electronicdevice is a remote control and the second electronic device is a displaydevice.
 10. The electronic system as claimed in claim 5, wherein theperpendicular distance X is defined by the following equation:$X = \frac{L \times \tan \; \theta_{1} \times \tan \; \theta_{2}}{{\tan \; \theta_{1}} + {\tan \; \theta_{2}}}$where θ₁ is a complementary angle for an angle of θ₃, the tangent ofwhich is the ratio of D₁ to F₁, and θ₂ is a complementary angle for anangle of θ₄, the tangent of which is the ratio of D₂ to F₂.